[INFO] cloning repository https://github.com/shterrett/rust-concurrency-tutorial
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/shterrett/rust-concurrency-tutorial" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fshterrett%2Frust-concurrency-tutorial", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fshterrett%2Frust-concurrency-tutorial'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 6d01f54064f6d679bbccd8da7a98835b5b216243
[INFO] checking shterrett/rust-concurrency-tutorial against master#385fa9d845dd326c6bbfd58c22244215e431948a for never-type-fallback-to-never
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fshterrett%2Frust-concurrency-tutorial" "/workspace/builds/worker-0-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/shterrett/rust-concurrency-tutorial on toolchain 385fa9d845dd326c6bbfd58c22244215e431948a
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/shterrett/rust-concurrency-tutorial
[INFO] finished tweaking git repo https://github.com/shterrett/rust-concurrency-tutorial
[INFO] tweaked toml for git repo https://github.com/shterrett/rust-concurrency-tutorial written to /workspace/builds/worker-0-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/shterrett/rust-concurrency-tutorial already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded chan v0.1.19
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 179a180a45d7e1c34708d84988d32dbab35ef5cdbef49bade6657b29e6082dbf
[INFO] running `Command { std: "docker" "start" "-a" "179a180a45d7e1c34708d84988d32dbab35ef5cdbef49bade6657b29e6082dbf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "179a180a45d7e1c34708d84988d32dbab35ef5cdbef49bade6657b29e6082dbf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "179a180a45d7e1c34708d84988d32dbab35ef5cdbef49bade6657b29e6082dbf", kill_on_drop: false }`
[INFO] [stdout] 179a180a45d7e1c34708d84988d32dbab35ef5cdbef49bade6657b29e6082dbf
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] e86d1de25837d76042b6a78ea376b25887f0ee9800c4cd8251fb7cb53ca726d3
[INFO] running `Command { std: "docker" "start" "-a" "e86d1de25837d76042b6a78ea376b25887f0ee9800c4cd8251fb7cb53ca726d3", kill_on_drop: false }`
[INFO] [stderr]     Checking libc v0.2.20
[INFO] [stderr]     Checking rand v0.3.15
[INFO] [stderr]     Checking chan v0.1.19
[INFO] [stderr]     Checking rust-concurrency-tutorial v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused `#[macro_use]` import
[INFO] [stdout]  --> src/main.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #[macro_use]
[INFO] [stdout]   | ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the item `drop` is imported redundantly
[INFO] [stdout]  --> src/main.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | use std::mem::drop;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^
[INFO] [stdout]  --> /rustc/385fa9d845dd326c6bbfd58c22244215e431948a/library/std/src/prelude/mod.rs:124:13
[INFO] [stdout]   |
[INFO] [stdout]   = note: the item `drop` is already defined here
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `#[macro_use]` import
[INFO] [stdout]  --> src/main.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #[macro_use]
[INFO] [stdout]   | ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the item `drop` is imported redundantly
[INFO] [stdout]  --> src/main.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | use std::mem::drop;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^
[INFO] [stdout]  --> /rustc/385fa9d845dd326c6bbfd58c22244215e431948a/library/std/src/prelude/mod.rs:124:13
[INFO] [stdout]   |
[INFO] [stdout]   = note: the item `drop` is already defined here
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 1.20s
[INFO] running `Command { std: "docker" "inspect" "e86d1de25837d76042b6a78ea376b25887f0ee9800c4cd8251fb7cb53ca726d3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e86d1de25837d76042b6a78ea376b25887f0ee9800c4cd8251fb7cb53ca726d3", kill_on_drop: false }`
[INFO] [stdout] e86d1de25837d76042b6a78ea376b25887f0ee9800c4cd8251fb7cb53ca726d3
[INFO] checking shterrett/rust-concurrency-tutorial against try#2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2 for never-type-fallback-to-never
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fshterrett%2Frust-concurrency-tutorial" "/workspace/builds/worker-0-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/shterrett/rust-concurrency-tutorial on toolchain 2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/shterrett/rust-concurrency-tutorial
[INFO] finished tweaking git repo https://github.com/shterrett/rust-concurrency-tutorial
[INFO] tweaked toml for git repo https://github.com/shterrett/rust-concurrency-tutorial written to /workspace/builds/worker-0-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/shterrett/rust-concurrency-tutorial already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] c1205be3606ca7f8d72c8c16f9f736132e62f52f554ea03349bc6e1fae070e16
[INFO] running `Command { std: "docker" "start" "-a" "c1205be3606ca7f8d72c8c16f9f736132e62f52f554ea03349bc6e1fae070e16", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "c1205be3606ca7f8d72c8c16f9f736132e62f52f554ea03349bc6e1fae070e16", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c1205be3606ca7f8d72c8c16f9f736132e62f52f554ea03349bc6e1fae070e16", kill_on_drop: false }`
[INFO] [stdout] c1205be3606ca7f8d72c8c16f9f736132e62f52f554ea03349bc6e1fae070e16
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 5b0da2001b851fbd20bd809d48b8e47a6c3e9d9202614701fc3bb05feaa884fd
[INFO] running `Command { std: "docker" "start" "-a" "5b0da2001b851fbd20bd809d48b8e47a6c3e9d9202614701fc3bb05feaa884fd", kill_on_drop: false }`
[INFO] [stderr]     Checking libc v0.2.20
[INFO] [stderr]     Checking rand v0.3.15
[INFO] [stderr]     Checking chan v0.1.19
[INFO] [stderr]     Checking rust-concurrency-tutorial v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused `#[macro_use]` import
[INFO] [stdout]  --> src/main.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #[macro_use]
[INFO] [stdout]   | ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the item `drop` is imported redundantly
[INFO] [stdout]  --> src/main.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | use std::mem::drop;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^
[INFO] [stdout]  --> /rustc/2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2/library/std/src/prelude/mod.rs:124:13
[INFO] [stdout]   |
[INFO] [stdout]   = note: the item `drop` is already defined here
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `#[macro_use]` import
[INFO] [stdout]  --> src/main.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #[macro_use]
[INFO] [stdout]   | ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the item `drop` is imported redundantly
[INFO] [stdout]  --> src/main.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | use std::mem::drop;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^
[INFO] [stdout]  --> /rustc/2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2/library/std/src/prelude/mod.rs:124:13
[INFO] [stdout]   |
[INFO] [stdout]   = note: the item `drop` is already defined here
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.80s
[INFO] running `Command { std: "docker" "inspect" "5b0da2001b851fbd20bd809d48b8e47a6c3e9d9202614701fc3bb05feaa884fd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5b0da2001b851fbd20bd809d48b8e47a6c3e9d9202614701fc3bb05feaa884fd", kill_on_drop: false }`
[INFO] [stdout] 5b0da2001b851fbd20bd809d48b8e47a6c3e9d9202614701fc3bb05feaa884fd